This invention relates generally to electromedical therapeutic apparatus and more specifically to an improved transcutaneous nerve stimulating apparatus for alleviating pain through the selective application of variable amplitude, variable pulse rate, variable pulse width electrical pulses to the skin in the area in which pain is experienced. It has been found that a proper application of such pulses serves to block the nerve responses and produce a beneficial effect.
In accordance with the teachings of the present invention, an integrated circuit timing network, energized by a rechargeable direct current battery is connected to an external resistor/capacitor charging circuit to form an astable oscillator whose pulse width and pulse rate are manually adjustable. The oscillator is coupled through a transistor current switching network and a step-up transformer to first and second pairs of electrodes. A current balancing network coupled between the output of the transformer and the electrodes allows the transformer output to be apportioned between the first and second electrode pairs. Another network, including a light emitting diode, is coupled to the integrated circuit timing network and is arranged to blink on and off when the rechargeable battery potential falls below a prearranged value, thus signaling the need for recharging.